Power-press.



Patented may 6, |902.

G. B. TENNA'NT.

POWER PRESS.

(Application led Aug. 4, 1909.)

.y (la Model.)

INVENTOR Patented May 6, |902. G. B.' TENNANT. Y

POWER PRESS. (implication n leamfg. 4, woo.)

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Unire STATES Arnim @prima GEORGE BuTENNANT, OF JOIINSTOVN, PENNSYLVANIA.

POWER-PRESS.

SPECIFICATIN forming part of Letters Patent No. 699,350, dated May 6,1902.

Application filed August 4,1900. Serial No. 25,890. (No model.)

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Beit known that I, GEORGE B. TENNANT, of Johnstown, Cambria county,Pennsylvania, have invented a new and useful Improvement inPower-Presses, of which the following is a full, clear, and exactdescription, reference being hadto the accompanying drawings, formingpart of this specification, in which- Fignre 1 is a side elevation,partly in section, ot'l a punching-press constructed in accordance withmyinvention. Fig. 2 is a front elevation of the same. Fig. 3 is avertical section on the line III III looking toward the rear. Fig. 4 isa side elevation, partly in section, ot a compression-riveter embodyingmy `invention. Fig. 5 is a front elevation of the same; and Figs. 6 and7 are sectional views on the lines VI VI and VII VII, respectively, ofFig. 4.

My invention relates to that class of presses and similar machineswherein power is applied through a toggle-joint device; and its objectis to improve the economy and cost of running of such machines and torender them adjustable for diierent classes of work by adjusting the Xedpivotal point of the toggle device. In machines of this class-such asriveters, punches, shears, presses, forging and upsetting machines,coining and embossing presses, bending -machines, &C.-there must be acertain allowance of stroke over and above the maximum rated capacity ofWork for clearance, stripping, dac. No useful work is done in thisportion of the stroke, as friction and weight of the parts only are tobe overcome, and consequently little power is required. This portion ofthe stroke also varies with dierent work.

My invention is designed to provide simple and eiective mechanism whichmay be applied to any machines of this character employing thetoggle-link actuating device and which will both adjust the tool quicklyand easily for different styles ot' work and also give the light portionof the stroke economically before the full power of the machine isapplied.

To that end the invention consists, broadly, in mechanism for adjustingthe fixed pivoted point of a toggle-joint wherein a longer and a shorterlever are pivoted together, and the power is applied directly to thejoint between these levers, thus adjusting the position of the toolbefore the working part of its stroke, and, further, in providingautomatic means for thus adjusting the tool and moving it through thenon Working portion of the stroke quickly and economically.

In the drawings, referring'to Figs. 1, 2, and 3, in which I show myinvention as applied to a punching-press, 2 represents a casting formingthe main frame of the machine, this casting being formed hollow toreceive the working parts. This frame is provided with the usual lowerdie-block 3, containing the holder and die 1l, there being aslot 5 belowthe die, through which the punchings are removed. The punch 6 is securedtothe lower end of a punch-stock, secured to a rectangular verticalplunger 7, moving in a suitable guide in the frame 2. This plunger isactuated by a steel operating-lever 8, having a fixed pivot 9 orfulcrum-pin carried in bearings in the main frame. To the rear end oflever 8 is connected the main pressure-links 10 of the toggle-joint, theupper ends of these links be-l ing pivoted to the pin 11 of thetoggle-joint.

The lower pin 12, connecting the links 10 and the lever 8, is providedlwith loose depending links 13, through whichextends a pin 14, the endsof which are secured in the main frame, as shown in Fig. 3. These linksserve to limit the motion of the operatinglever.

The main toggle-links 15 are connected at their upper ends to thepivot-pin 11 and at their lower ends to a rocker-bar 16, pivoted to theframe by a pin 17.

The toggle-joint is actuated by piston-rod 18, pivoted in the largetrunk portion 19 of piston 20. This piston is placed Within the mainmotive cylinder 21, which in the form shown is placed above the smallersupplemental cylinder 22. This small cylinder 22 is employed to adjustthe position of the main pin 11 of the toggle-joint through the links23, pivoted to the rock-arm at 24 and having at their upper endsprojections 25, which enter square inclined grooves in ahorizontallysliding head 26, connected to and actuated by the piston 27of the cylinder 22.V The head 2G slides on suitable guides on the mainframe by the movement of the small piston 27,vhich I have shown as movedto the center of its cylinder, bringing the plunger to the desired pointon the Work. This movement is caused by the action of the inclined facesof head 26, acting through the vertical links 23, the rocker-bar, theside links 15, the pressurelinks 10, and the main operating-lever. The

two arms of this main lever in the form shownv are of lengths in ratioof one to four, and a vertical movement of one inch of its plunger endwould give a movement of about four inches of the pin l2. To obtain thismovement would give a longer stroke of the small piston than isdesirable, and hence I employ the rocker-arm 16, to which the links 23are pivoted midway of its length. A vertical movement vof four inches atits outer pivot requires a movement of two inches at its pivotalconnection with the links 23. The inclined grooves in head 26 are at anangleof one to six, and the stroke of the small cylin*` der is twelveinches, thus giving the required movement. After this initial movementis given by admitting pressure at the front end of a small cylinder andmoving the head 26 toward the rear of the machine until the punch is incontact with the piece pressure is admitted to the rear end of the maincylinder, putting itspiston-rod in tension and actuating the toggle soas to raise the rear end of operating-lever S and force down the plungerto punch the hole. After the hole is punched pressure is admitted at thefront end of the cylinder 2l, thus reversing the action of the toggleand forcing the piston back to theposition shown. Pressure is thenadmitted to the rear end of the small cylinder 22, thus forcing down therocker-bar and the rear end of the operating-levers and lifting thepunch to clear it. A stripper is preferably provided to clear the punchfrom the metal, and the small cylinder thus does the work of stripping.

The valve mechanism for controlling the cylinders may be of any desiredform, and I have shown two rolling valves 29 in the heads of thecylinders, these being operated bythe single lever 30. The loose links13 serve to limit the stroke, and it is desirable to make the light partof the stroke as great as possible'. Hence in the case shown formaterial the form shown in these figures the togglejoint isintentionally arranged so that its greatest power is not applied. Thetoggle thus acts as a safeguard, so that if a piece of metal is insertedwhich is far beyond the capacity of the machine and the pressure appliedthere will be no injury to the machine, as the power is definitelylimited.

It will be noted that the main power is not used except when useful workis done. This gives longer life, owing to less wear of moving parts. Theslope of the grooves in the sliding block is equal to or a little lessthan the angle of friction, so that it gives a positive holding deviceat all points, and the pressure is transmitted through it direct vto themain frame by means of the tension-links.

In the case of a punch having a larger frame with greater depth ofthroat the rocker-bar would not be necessary, as sufficient movementcould be obtained from the sliding head.

It will be understood that my invention is applicable to many differentmachines, and in Figs. 4 to 7, inclusive, I show itapplied to acompression-riveter.. In these figures, 3l represents the main frameformed of the steel casting and havingits upper jaw of box form toreceive the rocker-bar This bar is pivoted to the pin 33, carried inbearings in the main frame, and is actuated by link 34, connected to itsrear arm by pin 35. The upper end of'this link is provided with lateralpro-v` jections 36, engaging the inclined square groove 37 ofhorizontally-slidinghead 38. This head slides on a suitable way on theupper jaw and is held down and guided by the guide-piece 39, which isbolted to the frame of the machine and extends over it, as shown in Fig.G. The head 3S is connected by a cross-head 40 with the piston-rod 41 ofthe small motive cylinder 42, and the cross-head is provided with anupward projection 43, which is arranged to strike the endof anadjustable stop or gage 44, which is adjustably clamped to the top ofthe guide-piece 39 by a clamp 45, secured by bolts 46. These bolts areactuated by wrench 47, and by means of the clamp the stop may be held inany adjusted position, thuslimiting the forward movement of the head 3S.

The main side links 43 of the toggle-joint are pivotally connected tothe front arm of the lever 32 by the trunnions or hubs 49 and at theirupper arms take about the main pin 50 of the toggle-joint. Thepiston-rod 5l, connected tothe trunk portion 52 of piston 53, isconnected at its front end to the main pin 50, and to this pin is alsoconnected the pressure-link 54 of the toggle-joint. This pressure-linkis pivotally connected to the upper enlarged portion of the plunger 55,which eX- tends down through a curved slot 56 in the lever 32 and isprovided at its lower end with the removable rivet die orsnap 57. Thelower rivet die or snap 58 is secured to the lower jaw in the usualmanner.

In the machine shown the movement of IOO the plunger 55 when operated bythe small cylinder 42 through the sliding head 38, link 34, and lever 32is four inches. The movement of the plunger 55 when operated by thetoggle-joint actuated by main cylinder is two inches. In using themachine, the main toggle being in the position shown in Fig. 4, it isbrought to the work and the plunger lowered by admitting pressure to therear end of small cylinder. A small block of metal two inches thick isplaced on the work and the plunger lowered by small cylinder until thedies grip the work and the two-inch piece. In practice the thickness ofthis block will be less than two inches, the plunger-stroke of maintoggle by the amount of deiiection of the steel frame of the machine asactually measured. The adjustable gage 44 will then be moved up tocontact with the cross-head and clamped in this position. The plungeris. then raised by admitting pressure to the front end of the smallcylinder and exhausting to its rear, and the block will be removed, andthe machine thus set for driving all rivets in this thickness of metal.

In driving the rivets the pressure is admitted to the small cylinder tomove the sliding block until stopped by the gage. It will be apparentthat the vertical motion of the plunger thus produced will not bring thetoggle-joint into play, but will change the position of the maintoggle-pin, this motion being allowed by the trunk on the main cylinderand the piston-rod turning on its pin in this trunk as the position ofthe main toggle-pin is adjusted. Pressure is then admitted to the rearend of the main cylinder, thus actuating the toggle-joint and forcingdown the plunger the stroke of the toggle and closing the rivet.Pressure then being admitted to the front end of the cylinder thetogglejoint is moved back to its normal inoperative position andpressure uid is then admitted to the smaller cylinder, thus giving afurther lift to the plunger.

-Tol equalize the angularity of the pistonrod 5l in the differentpositions of the main toggle-pin, the main cylinder is preferably placedso that its center line extends through the center of the maintoggle-pin when the joint is straightened, the adjusting-lever beingthen in its central position, asshown in Fig. 4.

Vhen the adjustable stop is fixed in its adjusted position, the machinewill operate properly on all work of the same thickness, and when usedon work of dierent thickness the stop will be correspondingly changed.

The advantages of my invention upon machines of this type will beappreciated by those skilled in this art, since the screw-piece whichhas heretofore been used toadj ust the upper rivet-die and which was asource of great trouble on account of distorting of the threads andbending and breaking of the screw under the heavy pressure is done awaywith. Moreover, the accidental changing of the position of the screw isobviated.

In this machine the cylinders may be operated by the large rollingslide-valve 59, placed in the common rear head of the cylinder andactuated by the single lever 60, or the cylinders may be controlled byany suitable valve mechanism.

The advantages of my invention result mainly from the adjusting of theiixed point of the toggle-joint, which feature I believe to be new andintend to cover broadly in its application to any machine of the generaltype described. As above shown, this feature lengthens the life of themachine and makes it more economical of power. The use of the inclinedabutment-blocks for adjusting is also of great advantage, as it enablesdifferent adjustments to be quickly and easily made to suit the machineto different classes of work and renders the machine compact and simple.

The invention may be applied to widelydiierent machines wherein power isexerted through a toggle-joint or direct cylinder, and the arrangementof the toggle-joint and the means for adjusting its vfixed point, aswell as the motive connections, may be varied widely without departingfrom my invention. In double drawing-presses the system may be used withtwo or more main toggles.

By the term power-press in the claims I intend to cover, broadly, anymachine wherein power is applied to the tool through a tog'- gle-jointconnection.

I claim l. A power-press having a toggle-joint, means for actuating thetoggle-joint, and power-actuated mechanism arranged to automaticallyadjust the ixed point of the toggle and thereby change the position ofthe tool; substantially as described.

2. A power-press having a toggle-joint arranged to actuate a tool, meansfor actuating the toggle-joint, and an inclined block having connectionsarranged to adj ust the fixed point ofthe toggle; substantially asdescribed.

3. A power-press having a toggle-joint arranged toactuate a tool, acylinder arranged to actuate the toggle-joint, and another cylinderhaving connections arranged to automatically adjust the fixed point ofthe toggle; the latter cylinder being of insufficient power to actuatethe tool in its working stroke, and arranged to merely adjust theposition of the tool substantially as described.

4. A power-press having a toggle-joint connected to and arranged toactuate a plunger, a lever connected to the plunger, and means forswinging the lever to adjust the ixed point of the toggle; substantiallyas described.

5. A power-press having a toggle-joint connected to and arranged toactuate a tool, a lever connected to the toggle, a link connected to thelever and having an inclined face, and a sliding block having aninclined face arranged to act upon the link to adjust the po- IOO IIO

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sition of the fixed point of the toggle; substantially as described.

6. A power-press having a toggle-joint connected to and arranged toactuate a tool, a lever connected to the main links of the toggle and'arranged to change the fixed point of the toggle, and mechanism forswinging the lever; substantially as described.

7 A power-press having a toggle-joint arranged to actuate a tool, acylinder arranged to actuate the toggle, and automatically-actingmechanism arranged to adj ust the position of the fixed point of thetoggle and drawing the tool to the desired point before the toggle-linkis actuated to move the tool; substantially as described.

8. A power-press having a toggle-joint arranged to actuate a tool, acylinder arranged to actuate the toggle-joint, and a smaller cylinderhaving connections arranged to adjust the fixed point of the toggle; thelatter cylinder being of insufficient power to move the tool through itsworking stroke substantially as described.

9. A power-press having a toggle-joint arranged to actuate a tool,mechanism for adj usting the fixed point of the toggle and an adjustablestop arranged to regulate the amount of said adjustment; substantiallyas described.

10. A power-press having a toggle-joint arranged to actuate a toolthrough a pressurelink, a lever connected to the main side links of thetoggle, a link connected to the lever and having an inclined face, asliding block arranged to act upon the link, an adjustable stop for theblock, and a power-cylinder connected to the block; substantially asdescribed.

ll. A power-press having a toggle provided with two levers of differentlengths connected together at their adjacent ends, the shorter l leverbeing arranged to actuate the tool, the longer lever having anadjustable fulcrum at its opposite end, said opposite ends of the leversboth being on the same side of the joint between the levers, means forapplying power to said joint, and mechanism for adjusting the fulcrum ofthe longer lever; substantially as described.

l2. A power-pressl having a toggle device formed with a longer and ashorter lever with their ends connected together, the opposite ends ofthe levers both being on the same side of the 'joint between the levers,a lever connected to the other end of the shorter lever and arranged toactuate the tool, means for applying power to the joint between the twotoggle-levers, and an adjustable fulcrum for the longer lever;substantially as described.

13. A power-press having a toggle-joint formed of a longer and a shorterlever pivotally connected at their ends, a power-cylinder connected tothe joint between the two toggle-levers, the opposite ends of the leversboth being on the same side of the joint between the levers, a thirdlever pivotally connected to the opposite end of the shorter lever andarranged to actuate the tool, a fixed fulcrum for the opposite end ofthe longer lever, and mechanism for adjusting said fulcrum;substantially as described.

14. A power-press having a toggle-joint formed of a longer and a shorterlever pivotally connected at their ends, a power-cylinder connected tothe joint between the two toggle levers, a third lever pivotallyconnected to the other end of the shorter lever and arranged to actuatethe tool, a fixed fulcrum for the other end of the longer lever, andmechanism for automatically adjusting the fulcrum to bring the tool tothe desired point; substantially as described.

In testimony whereof I have hereunto set my hand.

GEO. B. TENNANT.

Witnesses:

L. M. REDMAN, G. I. I-IoLDsHIP.

